1. UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
International General Certificate of Secondary Education
*2845008432*
CHEMISTRY
0620/31
Paper 3 (Extended)
May/June 2013
1 hour 15 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name on all the work you hand in.
Write in dark blue or black pen.
You may use a pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, highlighters, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
Electronic calculators may be used.
A copy of the Periodic Table is printed on page 12.
You may lose marks if you do not show your working or if you do not use appropriate units.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
This document consists of 12 printed pages.
IB13 06_0620_31/2RP
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2. 2
1
For
Examiner’s
Use
Petroleum contains hydrocarbons which are separated by fractional distillation.
(a) (i) Complete the following definition of a hydrocarbon.
A hydrocarbon is a compound which .........................................................................
.............................................................................................................................. [2]
(ii) Explain what is meant by the term fractional distillation.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(b) Some of the fractions obtained from petroleum are given below.
State a use for each fraction.
bitumen ....................................................................
lubricating fraction ...................................................
paraffin fraction ........................................................
gasoline fraction ......................................................
[4]
[Total: 8]
2
An element, M, has the electron distribution 2 + 8 + 18 + 3.
(a) Which group in the Periodic Table is element M likely to be in?
..................................................................................................................................... [1]
(b) Predict whether element M is a poor or a good conductor of electricity.
Give a reason for your answer.
..................................................................................................................................... [1]
(c) Binary compounds contain two atoms per molecule, for example HCl.
Identify an element which could form a binary compound with element M.
..................................................................................................................................... [1]
(d) Predict the formula of the sulfate of M. The formula of the sulfate ion is SO42–.
..................................................................................................................................... [1]
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3. 3
For
Examiner’s
Use
(e) The hydroxide of M is a white powder which is insoluble in water.
Describe how you could show that this hydroxide is amphoteric.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
[Total: 6]
3
A small piece of marble, CaCO3, was added to 5.0 cm3 of hydrochloric acid, concentration
1.0 mol / dm3, at 25 °C. The time taken for the reaction to stop was measured. The experiment
was repeated using 5.0 cm3 of different solutions of acids. The acid was in excess in all of the
experiments.
Typical results are given in the table.
experiment
temperature / °C
acid solution
1
25
hydrochloric acid 1.0 mol / dm3
3
2
25
hydrochloric acid 0.5 mol / dm3
7
3
25
ethanoic acid 1.0 mol / dm3
10
4
15
hydrochloric acid 1.0 mol / dm3
8
time / min
(a) (i) Explain why it is important that the pieces of marble are the same size and the same
shape.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(ii) How would you know when the reaction had stopped?
.............................................................................................................................. [1]
(b) The equation for the reaction in experiment 1 is:
CaCO3(s) + 2HCl (aq) → CaCl 2(aq) + CO2(g) + H2O(l)
Complete the following ionic equation.
CaCO3(s) + 2H+(aq) → ............ + ............ + ............
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[1]
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4. 4
(c) (i) Explain why the reaction in experiment 1 is faster than the reaction in experiment 2.
....................................................................................................................................
.............................................................................................................................. [1]
(ii) The acids used for experiment 1 and experiment 3 have the same concentration.
Explain why experiment 3 is slower than experiment 1.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(iii) Explain in terms of collisions between reacting particles why experiment 4 is slower
than experiment 1.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [3]
[Total: 10]
4
The structural formula of cyclohexane is drawn below.
CH2
H 2C
CH2
H 2C
CH2
CH2
(a) The name gives information about the structure of the compound.
Hex because there are six carbon atoms and cyclo because they are joined in a ring.
What information about the structure of this compound is given by the ending ane?
...........................................................................................................................................
..................................................................................................................................... [2]
(b) What are the molecular and empirical formulae of cyclohexane?
molecular formula .............................
empirical formula ..............................
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[2]
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5. 5
For
Examiner’s
Use
(c) Draw the structural formula of cyclobutane.
[1]
(d) (i) Deduce the molecular formula of hexene.
.............................................................................................................................. [1]
(ii) Explain why cyclohexane and the alkene, hexene, are isomers.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(e) Describe a test which would distinguish between cyclohexane and the unsaturated
hydrocarbon hexene.
test ....................................................................................................................................
result of test with cyclohexane ..........................................................................................
...........................................................................................................................................
result of test with hexene ..................................................................................................
..................................................................................................................................... [3]
[Total: 11]
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6. 6
5
The reactivity series shows the metals in order of reactivity.
(a) The reactivity series can be established using displacement reactions. A piece of zinc is
added to aqueous lead nitrate. The zinc becomes coated with a black deposit of lead.
Zn + Pb2+ → Zn2+ + Pb
Zinc is more reactive than lead.
The reactivity series can be written as a list of ionic equations.
...... →
...... + ......
Zn
→
Zn2+ + 2e–
Fe
→
Fe2+ + 2e–
Pb
→ Pb2+ + 2e–
most reactive metal : the best reductant (reducing agent)
Cu → Cu2+ + 2e–
Ag
→
Ag+ +
e–
(i) In the space at the top of the list, write an ionic equation for a metal which is more
reactive than zinc.
[1]
(ii) Write an ionic equation for the reaction between aqueous silver(I) nitrate and zinc.
.............................................................................................................................. [2]
(iii) Explain why the positive ions are likely to be oxidants (oxidising agents).
.............................................................................................................................. [1]
(iv) Deduce which ion is the best oxidant (oxidising agent).
.............................................................................................................................. [1]
(v) Which ion(s) in the list can oxidise lead metal?
.............................................................................................................................. [1]
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7. 7
(b) A reactivity series can also be established by measuring the voltage of simple cells. The
diagram shows a simple cell.
For
Examiner’s
Use
voltmeter
V
cadmium
electrode
copper
electrode
sulfuric acid
Results from cells using the metals tin, cadmium, zinc and copper are given in the table
below.
cell
electrode 1
positive electrode
electrode 2
negative electrode
voltage / volts
1
copper
cadmium
0.74
2
copper
tin
0.48
3
copper
zinc
1.10
Write the four metals in order of increasing reactivity and explain how you used the data
in the table to determine this order.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
[Total: 9]
6
Ammonia is a compound which only contains the elements nitrogen and hydrogen. It is a
weak base.
(a) (i) Define the term base.
.............................................................................................................................. [1]
(ii) Given aqueous solutions of ammonia and sodium hydroxide, both having a
concentration of 0.1 mol / dm3, how could you show that ammonia is the weaker
base?
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
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8. 8
(b) Ammonia is manufactured by the Haber Process. The economics of this process require
that as much ammonia as possible is made as quickly as possible.
Explain how this can be done using the following information.
The conditions for the following reversible reaction are:
●
●
●
450 °C
200 atmospheres pressure
iron catalyst
N2(g) + 3H2(g)
2NH3(g)
the reaction is exothermic
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [5]
(c) Another compound which contains only nitrogen and hydrogen is hydrazine, N2H4.
Complete the equation for the preparation of hydrazine from ammonia.
.....NH3 + NaCl O → N2H4 + ............ + H2O
[2]
(d) The structural formula of hydrazine is given below.
H
H
N
H
N
H
Draw a diagram showing the arrangement of the valency electrons in one molecule of
the covalent compound hydrazine.
Use x to represent an electron from a nitrogen atom.
Use o to represent an electron from a hydrogen atom.
[3]
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9. 9
(e) Hydrazine is a weak base and it removes dissolved oxygen from water. It is added to
water in steel boilers to prevent rusting.
For
Examiner’s
Use
(i) One way it reduces the rate of rusting is by changing the pH of water.
What effect would hydrazine have on the pH of water?
.............................................................................................................................. [1]
(ii) Give a reason, other than pH, why hydrazine reduces the rate of rusting.
.............................................................................................................................. [1]
[Total: 15]
7
The hydroxides of the Group I metals are soluble in water. Most other metal hydroxides are
insoluble in water.
(a) (i) Crystals of lithium chloride can be prepared from lithium hydroxide by titration.
burette filled with
hydrochloric acid of
concentration 2.20 mol / dm3
conical flask
25.0 cm3 of aqueous lithium hydroxide
and indicator
25.0 cm3 of aqueous lithium hydroxide is pipetted into the conical flask.
A few drops of an indicator are added. Dilute hydrochloric acid is added slowly to the
alkali until the indicator just changes colour. The volume of acid needed to neutralise
the lithium hydroxide is noted.
A neutral solution of lithium chloride, which still contains the indicator, is left. Describe
how you could obtain a neutral solution of lithium chloride which does not contain an
indicator.
....................................................................................................................................
.............................................................................................................................. [2]
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10. 10
(ii) You cannot prepare a neutral solution of magnesium chloride by the same method.
Describe how you could prepare a neutral solution of magnesium chloride.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [3]
(b) The concentration of the hydrochloric acid was 2.20 mol / dm3. The volume of acid needed
to neutralise the 25.0 cm3 of lithium hydroxide was 20.0 cm3. Calculate the concentration
of the aqueous lithium hydroxide.
LiOH + HCl → LiCl + H2O
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(c) Lithium chloride forms three hydrates. They are LiCl.H2O, LiCl.2H2O and LiCl.3H2O.
Which one of these three hydrates contains 45.9 % of water?
Show how you arrived at your answer.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
[Total: 10]
8
There are three types of giant structure - ionic, metallic and giant covalent.
(a) In an ionic compound, the ions are held in a lattice by strong forces.
(i) Explain the term lattice.
....................................................................................................................................
.............................................................................................................................. [2]
(ii) Explain how the ions are held together by strong forces.
....................................................................................................................................
.............................................................................................................................. [1]
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11. 11
For
Examiner’s
Use
(b) Describe the bonding in a typical metal.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
(c) The electrical conductivities of the three types of giant structure are given in the following
table.
type of structure
conductivity of solid
conductivity of liquid
ionic
poor
good
metallic
good
good
giant covalent
poor
poor
Explain the differences in electrical conductivity between the three types of giant structure
and the difference, if any, between the solid and liquid states of the same structure.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [5]
[Total: 11]
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12. © UCLES 2013
24
40
Sodium
Calcium
88
0620/31/M/J/13
89
Key
b
X
a
72
b = proton (atomic) number
X = atomic symbol
a = relative atomic mass
*58-71 Lanthanoid series
90-103 Actinoid series
88
Ac
Actinium
Ra
Radium
Fr
Francium
87
*
Hafnium
Lanthanum
57
Hf
La
40
Zirconium
Zr
91
Titanium
178
Yttrium
22
48
Ti
139
39
Y
89
Scandium
21
227
Caesium
56
Barium
Cs
45
Sc
226
55
137
Ba
133
Strontium
Rubidium
38
Rb
37
Sr
85
20
Potassium
19
Ca
39
Magnesium
Na
12
Mg
23
Beryllium
4
Lithium
K
11
3
9
Be
7
II
Li
I
51
93
Ta
181
Niobium
Nb
90
58
73
52
96
Mo
W
184
141
Pa
Thorium
55
Tc
186
Re
144
Nd
92
60
Uranium
U
238
Neodymium
75
Rhenium
43
Technetium
25
Manganese
Mn
29
30
65
8
9
VII
2
0
Ru
101
Iron
190
Pm
Osmium
Os
93
Np
Neptunium
61
Promethium
76
44
Ruthenium
26
56
Fe
Sm
150
Iridium
94
Pu
Plutonium
62
Eu
152
Platinum
95
Am
Americium
63
Europium
78
195
Pt
192
46
Palladium
Pd
106
Nickel
Ni
Ir
Samarium
77
45
Rhodium
Rh
103
Cobalt
Co
Gd
157
Gold
Au
197
Silver
96
64
Curium
Cm
Gadolinium
79
47
Ag
108
Copper
Cu
201
Bk
Terbium
Tb
159
Mercury
Hg
97
Berkelium
65
80
48
Cadmium
Cd
112
Zinc
Zn
11
70
Dy
162
Thallium
Tl
204
Indium
98
Cf
Californium
66
Es
Holmium
Ho
165
Lead
Pb
207
Tin
99
Einsteinium
67
82
50
119
Sn
In
32
Germanium
Ge
73
Silicon
115
Gallium
Ga
Dysprosium
81
49
31
13
Aluminium
Si
Al
14
28
Carbon
27
Boron
12
C
14
75
Sb
122
Arsenic
As
Bi
209
Fermium
Fm
Erbium
Er
167
Bismuth
100
68
83
51
Antimony
33
15
Phosphorus
P
31
Nitrogen
N
Se
79
Sulfur
S
32
Oxygen
Po
169
Md
Thulium
Tm
101
Mendelevium
69
84
Polonium
52
Tellurium
Te
128
Selenium
34
16
16
O
Yb
173
Astatine
At
Iodine
I
127
Bromine
Br
80
Chlorine
No
102
Nobelium
70
Ytterbium
85
53
35
17
Cl
35.5
Fluorine
F
19
Lr
Lutetium
Lu
175
Radon
Rn
Xenon
Xe
131
Krypton
Kr
84
Argon
Ar
40
Neon
103
Lawrencium
71
86
54
36
18
10
Ne
20
Helium
Hydrogen
B
4
28
64
7
VI
He
27
59
6
V
H
59
5
IV
The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).
91
Protactinium
Th
232
Praseodymium
Cerium
59
Pr
Ce
74
Tungsten
42
Molybdenum
24
Chromium
Cr
140
Tantalum
41
23
Vanadium
V
1
III
1
Group
DATA SHEET
The Periodic Table of the Elements
12
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